66431866 has 32 divisors (see below), whose sum is σ = 113270400. Its totient is φ = 29050560.

The previous prime is 66431863. The next prime is 66431879. The reversal of 66431866 is 66813466.

It is not an unprimeable number, because it can be changed into a prime (66431863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24036 + ... + 26656.

It is an arithmetic number, because the mean of its divisors is an integer number (3539700).

Almost surely, 2^66431866 is an apocalyptic number.

66431866 is a deficient number, since it is larger than the sum of its proper divisors (46838534).

66431866 is a wasteful number, since it uses less digits than its factorization.

66431866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2694.

The product of its digits is 124416, while the sum is 40.

The square root of 66431866 is about 8150.5745809728. The cubic root of 66431866 is about 405.0035380476.

The spelling of 66431866 in words is "sixty-six million, four hundred thirty-one thousand, eight hundred sixty-six".